Monday, December 1, 2014

Warmer oceans matter

Some people might argue that oceans aren't warming much and so we've lots of time to mitigate global warming. (See recent article.)

Thing is oceans are warming quickly, and it does matter. It matters to the creatures that live in the oceans for a start. Anyone who has had an aquarium knows that some fish are very sensitive to temperature. Sure, they can swim to where it's cooler if it gets too hot for comfort but there's no guarantee they'll find a source of food there that they like. Many fish have been moving to cooler waters as fishers have known for a while. The fish in the coolest waters don't have any such luck. They've run out of options. Add warming oceans to increasing acidification and marine life is getting a double whammy. (Which reminds me, I must finish that promised article soon.)

It also matters to species like us who live on the surface. That's not just because it affects a major source of food (fish) but because of the ocean-atmosphere connections. Warmer oceans means a warmer ocean surface, which has an impact on surface temperatures on the land as well. Plus there are impacts on ocean currents (with consequences for the atmosphere) and melting ice, which are not insignificant.

"Changing a unit to have a small sounding number doesn't actually change anything"

Deniers tend to downplay ocean warming, calling it "minuscule". Some will quote the change in ocean temperature rather than the change in ocean heat content. As Gavin Schmidt once wrote in a comment on this subject at realclimate.org, when someone else wanted to talk about the energy accumulated as a temperature rise rather than joules:

Changing a unit to have a small sounding number doesn’t actually change anything; neither the significance nor the accuracy. .... – gavin

It takes an awful lot of energy to have a measurable rise in temperature of a body of water measuring 1.3 billion cubic kilometers. We are very fortunate to have such a large body of water to soak up most of the extra energy we've decided to store on earth.

Just think. If instead of warming the ocean, all the extra energy that went into the oceans over the past thirty years or so instead went into warming the atmosphere. Here's a chart of ocean warming again:

Here's a quick calculation. Say since around 1980 there's been approximately 2 x 1023 joules of energy accumulated in the ocean. (That's just a rough number, but we'll use it for the sake of the exercise.) The atmosphere has a mass of 5 x 1018 kg and a heat capacity of 1000 J/kg/K. That means that if instead of going into the ocean, that energy had gone into warming the air, then the atmosphere would be around 40°C hotter than it is today - and none of us would be around to realise it.

Of course it didn't happen and it won't and can't. Not only does the ocean absorb most of the extra energy, but there are mechanisms like the water cycle, which moderate the warming.

Still, it's just another way of thinking about what we are doing by warming the globe.

I'll add this graphic from SkepticalScience.com. It's a bit old, being based on the IPCC AR4 report, but it's close enough. It illustrates where all the extra energy is going,

Bob hasn't added much since his last article on the subject, which I wrote about already. He is still trying (and mostly succeeding) in persuading his readers that the oceans have only warmed a "minuscule" amount. He's wrong of course, as usual.

Bob also seems to think my recent article was "reality impaired" and "nonsensical" but he doesn't say what he found unreal about it or which bits he thought were nonsense. On the contrary, in his latest article, about the only thing new was that he added the chart of ocean heat content, and acknowledged that 90% of the extra energy is going into the oceans. Both of these ideas were a direct take from my article, which contradicts his allegations of nonsensical and unreal. You could call it his homage to HotWhopper. (He also almost, but not quite, thanked me for deleting his address from one of the comments. It's a shame he doesn't share my respect for the privacy of other people.) Oh, and he managed to find a search term that will bring up all his drawings in Google, at least for him, if you're interested. Which I doubt. Not everyone will find the same.

From the WUWT comments

Although this isn't predominately an article about WUWT, I'll still give you a some gems from the comments to Bob's latest article.

mwh wants to wait for a "cooling cycle" before he accepts global warming.

November 30, 2014 at 5:43 am
I find it incredible that after just 10years of data there is an assumption in the warmist camp that we now know what the oceans are doing when it comes to heat. Also I note that a lot of CAGW graphs on the top 2000m use a start date in the 1950s as if the data accurately and continuously goes back to then.
Until we have completed a global warming and cooling cycle we cant possibly know what, how and when the oceans are storing/releasing heat. 60 years maybe…..that would be 2 climate cycles at least. I would think that it is more likely to be centuries before full sense of the data can be made

November 30, 2014 at 8:31 am
I made the unfortunate choice of clicking on a link in the article which brought me to hot whopper. In an earlier response to a comment I suggested alarmists would be soon claiming boiling oceans, but yet was still surprised to see this heading to the article the link brought me to.
“Why did the water in the kettle boil? Because it got hot!

Yes, that is correct the ocean temperatures rising at a rate of 3 hundredths of a degree centigrade per decade warrants a comparison to a kettle of boiling water. Hot Whopper, apparently a place where common sense is avoided like Ebola. I was tempted to a add a comment telling them to no longer invest in saunas since in 15,000 years the oceans will be boiling, but then thought better of it. Who knows maybe stupid is more contagious than Ebola at Hot Whopper.

November 30, 2014 at 1:02 pm
i have a question.
It seems to me that the oceans did not magically start absorbing heat when CO2 rose a few years back. The oceans must have been absorbing heat before CO2 rose. Even if we grant that there has been a rise in surface temperature of a couple degrees with the rise in CO2 — that rise in temperature is very small compared to the previous surface temperature. (Starting surface temp. +_extra CO2 heat of a couple of degrees is still almost the same as the starting surface temperature.)

Therefore most of the heat absorbtion occurring now was occurring before the rise in CO2. So if you measure the heat rise of the oceans now — it must be rising at almost exactly the same rate as it was before the rise in CO2 and the extra heat that CO2 has supposedly generated.

So it seems to me whatever rise is being measured in ocean temperature is “natural” and is a function of the surface temperature and has been occurring for thousands of years — with the new extra CO2 heat adding practically nothing to that rise.

You seem to be attributing all the rise in ocean temperature (as small as it may be) to CO2 heat. But really on a tiny tiny percentage of that tiny tiny rise could possible be caused by CO2 heat.

My question? What am I missing? I drank more Wild Turkey for Thanksgiving than I ate of turkey and seem to have suffered extensive brain damage. So is my idea a turkey that can’t fly???
Eugene WR Gallun

jimmi_the_dalek is a rare bird at WUWT. I haven't checked his statement about the top 3 metres of ocean, but his conclusion is on the money.

November 30, 2014 at 1:35 pm
Well it is just as well the heat is hiding in the oceans. I remember reading that the top 3 metres of the ocean has as much heat capacity as the whole of the atmosphere. So if enough heat is accumulating that the top 2000 metres is raised by 0.03C/decade, just think what would have occurred if all that heat had ended up in the atmosphere – better hope we don’t get any 1998 style El Nino’s soon.

John Finn is the other rare bird. Again, I haven't checked his calculations but again his conclusion isn't bad. There were only two such rare birds I noticed, out of 149 comments. Or 1.34% of the people commenting. Now that's what I call minuscule.

November 30, 2014 at 4:20 pm
While Bob’s post is undoubtedly correct, it is worth noting that the accumulation of energy in the oceans looks to be reasonably consistent with Hansen’s energy imbalance estimate of 0.85 watts/m2.

If we assume all ‘excess’ energy has gone into the oceans since 2005, i.e. the surface/air temperature has remained unchanged and nothing has gone towards melting ice then the 8.64×10^22 Joules per decade equates to an imbalance of ~0.76 watts per m2. That’s based on a quick calculation made after a couple of pints and a brandy so I could be wrong – but I don’t think I’m too far out.

If correct, though, it does suggest that surface warming could pick up quite strongly again in the future.

33 comments:

In what? The top 2000 m? Yes, that's incredibly fast. You're looking at almost 2 x 10^23 joules over three decades.

Do you have any idea of how much energy that takes? Look at the sidebar. Since 1970 the earth has accumulated the equivalent of more than 542,285,700,000,000 lightning bolts or 4,404,855,000 6.0 earthquakes and most of that has been accumulated in the oceans.

"Changing a unit to have a small sounding number doesn’t actually change anything; neither the significance nor the accuracy." - nor does it diminish the importance (or speed).

First they need to imagine a 3 Kilowatt fan heater raising the temperature in a cold room by 10 degrees. How long would it take? 15 minutes reasonable?

Second, imagine the same room now filled with water and a 3 Kilowatt immersion heater fitted so as to enable the water temperature to be again raised by 10 degrees. So how long would that take? Well I'm not up to the maths but I'm going to guess at least 24 hours, which is roughly 100x longer. I'm sure a physicist could quite easily work it out, I'd love to know.

And the point is: a tiny temperature rise in the ocean is as significant as a large temperature rise in the atmosphere.

David Appell did a calculation recently about what a very small change in ocean heat uptake means for the trend.

His article is here:http://davidappell.blogspot.dk/2014/11/when-just-litllllllllle-more-heat-goes.htmlThe main message:0.1% more ocean uptake is -0.024 degrees decadal trend0.5% more ocean uptake is -0.12 degrees decadal trendAll ballpark calculations, but it shows how enormous the effect of a small change in ocean uptake can be.

Maybe Sou mentioned this (I haven't read the post in detail, sorry :-) ) but the upper 300m accrues about half of the energy increase. The lower 1700m accrues the other half. Therefore, the upper 300m warms about 7 times faster than the average for the ocean as a whole. So, the average for the entire ocean may be around 0.02 degrees per decade, but for the upper 300m it is around 0.15 degrees per decade.

If I understand it properly, this is because the upper 100m or so of the ocean is well-mixed and equilibrates with the atmosphere very quickly (a few years). Therefore the rate at which the well-mixed layer warms is a reasonable estimate for the rate at which the surface will warm. The deep ocean equilibrates much more slowly through an essentially diffusive process. Therefore we can get the atmosphere and well-mixed layer close to equilibrium quickly (decades) but it then takes centuries for the entire system to reach equilibrium. Hence the surface will warm much faster than the rate at which the ocean as a whole warms on average (and by warm, I mean increase in temperature, rather than increase in energy).

Which is perfectly valid as a concept. The problem I'm encountering is that such temperatures can be reliably measured with the required resolution.

As for your example of the fan heater, the time it takes for the fan to raise the temp of the room depends on the starting temp of the room, even if you ignore all other sources of variation. As the room warms, the heat transfer from heater to room becomes less efficient. Meaning that the first degree of room warming occurs the most quickly, and the warming from the ninth to tenth degrees of additional temp will take the longest of each of the ten degrees of delta.

Since all we have for temperature measurement for long ago is proxy data, can you please share the calibration of that proxy data? I've always wondered how accurate can be a measurement of something that happened before modern science was around with instruments to measure it.

Energy is conserved. Energy in the upper ocean layer will out, sooner or later. It doesn't just vanish forever.

Nor is this necessary for the rate of surface warming to increase. A reduction in the rate of ocean heat uptake would be sufficient.

Surface warming is an inevitable consequence of a planetary energy imbalance. Short-term variability in the rate of ocean heat uptake modulates the rate of surface warming but doesn't invalidate basic physics. Energy is conserved.

And you could change the rate of increase in ocean heat content from years to minutes and get an even smaller number. Crawl back into your hole troll. We are discussing science here.

So Tisdale claims that ocean warming is "miniscule" at the same time as claiming that the record 2014 atmospheric temperatures are a result of ocean warming. (see http://blog.hotwhopper.com/2014/11/why-did-water-in-kettle-boil-because-it.html) Good old Bob. Never let an obvious logical fail or the laws of physics get in the way of feeding the climate cranks the story they want to hear.

Thermal expansion is a "thermometer". If sea level rise (SLR) was inconsistent with measured warming, corrected for known loss of stored water and ice on land, you wouldn't get consistent (within error bars) SLR.

It's a fair question whether we understand the oceans well enough to judge its uptake of excess planetary heating, but the "answer" is better measurements and consistency checks, not pretending the the planet isn't accumulating heat.

JLH: "... the time it takes for the fan to raise the temp of the room depends on the starting temp of the room, even if you ignore all other sources of variation."

As this is a thought experiment, and we have a perfectly insulated room, with perfect mixing of the fluid, let's make the 3kW heater have a very high temperature - say 200 deg. C. So there is effectively no difference in the delta T (and rate of conductive heat transfer) when it is heated by 10 degrees.

You've missed the point, we are discussing total energy, not temperature. As water has a much higher specific heat and is much more dense than air, it holds more energy. Temperature is not sufficient to measure energy - consider a 1kg mass of ice at 0 deg. and the same mass of water at 0 deg. - same temperature, but the water contains much more heat (aka energy) than the ice. A simple calculation shows that the energy necessary to melt 1kg of ice at 0 deg. to water at the same temperature would be the same amount of energy required to heat 1kg of water from 0 deg. to 80 deg. (approximately, doing the numbers in my head).

My comment is Off Topic so move, edit or hold for some other time if appropriate (just don't know how to get this to you otherwise): Salon has an interesting article by Paul Rosenberg concerning the issue of why some people "just don't get it." The article is oriented toward understanding the disparity in the US political system (voters) but provides useful insight into the reasons some deniers, in spite of what we all recognize as facts and science, hold onto the myths for so long, if not forever. Included is a very enlightening interview with David Dunning. With respect to climate change, the "problem", if I can transfer from the article, is not so much a lack of math and science skills as it is a world view (e.g., "mythos") where math and science are discounted and held secondary in importance. This "world view" (of which there is at least one alternate which you - and I - most definitely hold) appears to be a fundamental human condition set in the brain (by genetics? environment?). You and your readers might find it interesting. It has certainly put the issue of "why deniers grasp myths so tightly" into perspective and helped mitigate some of the frustration I feel about the seemingly nonsensical arguments and comments elsewhere. Unfortunately, the "mythos" world view is probably self-destructive in the long run, but may have evolved to help humans survive in some way (human interactions, family, social?), perhaps providing a short term advantage sacrificing the long term - "we'll cross that bridge when we get to it." As we of alternate world views realize, this approach does not work in the case of climate change.The article is at: http://www.salon.com/2014/11/29/why_are_these_clowns_winning_secrets_of_the_right_wing_brain/

"Unfortunately for all of us, policies and decisions that are founded on ignorance have a strong tendency, sooner or later, to blow up in one’s face. So how can policymakers, teachers, and the rest of us cut through all the counterfeit knowledge—our own and our neighbors’—that stands in the way of our ability to make truly informed judgments?

The way we traditionally conceive of ignorance—as an absence of knowledge—leads us to think of education as its natural antidote. But education, even when done skillfully, can produce illusory confidence."

You're right that the energy content is much higher, but it's a mistake to speak of a body as containing any fixed amount of heat. "Heat" isn't an all-purpose synonym for energy, but is more specifically energy that is transferred spontaneously because of a temperature difference. There's no fixed amount of "heat" in a body, but the energy content is well-defined.

For example, if you have a hot gas, you might extract its energy by allowing it to do work, or you might simply let it cool You'd end up at the same temperature, but the amount of heat extracted would be different.

A pedantic point, perhaps, but it caught my eye because I've taught this so many times by now.

Yes and no. It's all a bit complex as the temperature increase also affects the acid-base equilibria of dissolved CO2. The effect of temperature increase in reduced uptake is likely limited. You really have to heat the oceans a lot before the equilibrium is altered significantly.

Sadly my professional workload has increased enormously over the last year and I do not have the time to engage in fora such as Sou's nearly as much as I would like, but I'm pleased to see that the quality of refutation of denialism here is excellent, as ever. Kudos to all of you who are maintaining the high standard of correction, correction, correction in the face of knuckle-dragging sutpidity.

It's also sad to see that the Dunningly-Krugered nonsense of those such as Tisdale is as recalcitrantly and stupidly ignorant as it ever was, even after years of presistent attemtps to enlighten them.

The inescapable fact is that global warming is real. Any dancing around the 'relatively' small magnitude of warming completely fails to understand this magnitude in context. For stupid people like Watts and Tisdale, it can perhaps be simply put thus: the amount of warming that the global ecosystem is experiencing is about as significant as if the same temperature anomaly was occurring in a eutherian mammal of the non-hibernating/æstivating sort. Half a degree Celsius is serious, and will affect the system, but it is not immediately lethal. A degree is cause for real concern for the ongoing functioning of the system. Two degree is worse, seriously worse, and four degrees is basically goodbye to the system as you knew it.

And if such an increase is serious for humans over hourse or days, it no different when such warming takes decades at the global level and persists for centuries/millenia at the global level, as this is still less than the time frame in which genetic evolution and coadaptation processes are able to respond.

Every time a climate change denier opens their mouth or puts fingers to keyboard, all they seem to be able to do it produce a testimony to their unredeemable ignorance. And such ignorance that it is a crime against hunity and nature.

"As the room warms, the heat transfer from heater to room becomes less efficient."

If it's an electric heater, then the efficiency remains almost exactly the same as the room warms. 3,000W is 3,000W. That is, unless the room becomes so very warm that the electric filament (resistor) in the radiator would also warm significantly, become more resistive as a result, and the electric power is reduced under the constant voltage input.

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All you need to know about WUWT

WUWT insider Willis Eschenbach tells you all you need to know about Anthony Watts and his blog, WattsUpWithThat (WUWT). As part of his scathing commentary, Wondering Willis accuses Anthony Watts of being clueless about the blog articles he posts. To paraphrase:

Even if Anthony had a year to analyze and dissect each piece...(he couldn't tell if it would)... stand the harsh light of public exposure.

Definition of Denier (Oxford): A person who denies something, especially someone who refuses to admit the truth of a concept or proposition that is supported by the majority of scientific or historical evidence.
‘a prominent denier of global warming’
‘a climate change denier’

Alternative definition: A former French coin, equal to one twelfth of a Sou, which was withdrawn in the 19th century. Oxford. (The denier has since resurfaced with reduced value.)